THE BODY AT WORK 



CHAPTER I 



PROLEGOMENA 



PHYSIOLOGY is the science of the body at work. It is the study 

 of life. Anatomy records how plants and animals are con- 

 structed. It maps and measures. Physiology ascertains what 

 they do, endeavours to explain how they do it, and conjectures 

 why. 



A knowledge of structure is essential to the right under- 

 standing of function ; but the physiologist does not contemplate 

 structure with a view to divining possibilities of action. He has 

 no interest in structure as such. To him it is a matter 

 of perfect indifference whether the tendon of a muscle is at 

 its origin or its insertion. He would rather not know which 

 end of the muscle terminates in a tendon. It is waste of his 

 time to notice such a fact, save for the negative, the protective 

 value of the information. If he did not know how the 

 muscle and tendon are related, he might possibly imagine 

 the muscle as doing something of which it is incapable. 

 Observers of living things are often credited with studying 

 structure with a view to determining function. The reverse 

 is the true order of thought and observation. Living things 

 perform certain acts. Having no inherent knowledge of our 

 own microcosm which enables us to say how it works, we 

 cannot, by reflecting upon our own internal operations, explain 

 its various activities. Nor can we make use of the results of 

 introspection when endeavouring to account for the acts of 

 other beings. Our knowledge of how things are done is 

 altogether extrapersonal, objective. It is the result of trial, 

 failure, success in the use of apparatus, our own essays, or those 

 of others. The body is a combination of organs a term 



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